In general, a roller type one-way clutch is constituted by an outer race, an inner race disposed coaxially with the outer race, a plurality of rollers disposed between an outer peripheral surface of the inner race and an inner peripheral cam surface of the outer race and adapted to transmit torque, and springs contacted with the rollers at an idle rotation side.
With this arrangement, in the one-way clutch, the inner race is rotated only in one direction with respect to the outer race by a cam mechanism constituted by the rollers and the cam surface. That is to say, the inner race is designed so that the inner race is idly rotated with respect to the outer race in one direction and serves to transmit rotational torque to the outer race via the cam mechanism only in the opposite direction.
In general, in the roller type one-way clutch, i order to obtain positive engagement, the rollers as torque transmitting members and the springs for biasing the rollers are arranged in respective pockets formed in the outer race or the inner race.
Particularly, in a roller type one-way clutch for a motor bike, since the number of rollers is small (for example, three or six), if all of the rollers are not engaged with the corresponding cam surfaces positively, a design torque capacity may not be obtained. Thus, it is important that the springs for biasing the rollers are operated stably.
Japanese Patent Application Laid-open No. 2003172377 discloses a technique in which cage portions are provided in pockets to prevent the rollers and the springs from dislodging toward an inner peripheral side of the outer race. However, this document does not teach the fact that the springs are secured to the outer race.
If accordion springs are merely held with respect to the outer race, relative positions between the accordion springs and the outer race cannot be determined or stabilized, with the result that, when the springs are slidingly contacted with an inner diameter portion of the outer race, an outer diameter portion of a cage or a track surface of the inner race, the springs may be worn or damaged by wear. Further, there arose a problem that, in operation, movements of the springs cannot be stabilized, with the result that it is hard to obtain smooth movements.